Hot water low temp on NIBE s1255

[AlSmith]

Hi, I have pretty much got my GSHP working very well and balanced for heating but my water temp has suddenly decided to cut off when it reaches 40-44 Degrees.  It used to cycle nicely between 50 and 55.  The demand is set to medium and the installer settings are on at 40 and off at 55 but it only gets up to mid 50s now  if I manually select ‘add hot water’ as a one off event.  I did mistakenly reset the initial settings but have rest curve and checked demand so a bit confused now that it doesn’t get higher than 44 degrees.  Prioritisation is set to auto, and when no heating demand water still cuts off at 44 ish. 

[JohnMo]

38 minutes ago, AlSmith said:

cuts off at 44

Is there a weather compensation curve set?

[AlSmith]

No haven’t tinkered with that yet, so still set at 0.  The water behaviour changed after my unintentional reset but what I can’t be certain of is what the installer changed from factory settings (if anything). All I had changed thereafter was the curve, dependent upon whether we were at the house or down south ( we are only up sporadically so keep the bills down when not there) during all that time though the water was always a constant cycle. 

[AlSmith]

Just to clarify my last post, the NIBE has a variety of tweaks which affect flow rate, curve heating which is set to 6, point offset both outdoor temp point and change in curve are set to 0 degrees, lowest supply heating is set to 20 and highest supply heating set to 40 ( it’s connected to UFH) .

[AlSmith]

Hi, Thanks for assistance and views, happy to close off as now rectified. The NIBE was in ‘away mode’ which I found under a sub sub menu, every day is a school day!